In the first round of the Western & Southern Open at Mason, Ohio, Keys defeated American wild-card entrant Bethanie Mattek-Sands 3-6, 7-6 (3), 6-4.

After losing in the third round at Wimbledon to Russian qualifier Evgeniya Rodina, Keys pulled out of events in San Jose, Calif., and Montreal because of a right wrist injury.

Mattek-Sands, who is in her first year back from a ruptured patella tendon suffered at Wimbledon in 2017, captured the first set and was on top 3-1 in the second, one point from going up by two service breaks, before Keys rallied.

“That was a little bit dramatic, but I’m happy to get through and get to play another match,” Keys said in her post-match interview on the court. “It’s always tough playing a friend and on top of that, knowing her story and how hard she’s fought to come back. It’s always difficult when you have someone that you care about on the other side of the net.”

The only other seeded player in early action Monday was knocked out due to an injury. A left calf injury forced 10th-seeded Julia Goerges of Germany to retire while trailing France’s Kristina Mladenovic 6-4, 3-2.

The 2013 Western & Southern champion, Victoria Azarenka of Belarus, came from behind for a 6-7 (5), 6-2, 6-4 win over Spain’s Carla Suarez Navarro.

The tournament’s top eight seeds, including No. 1 Simona Halep of Romania, No. 2 Caroline Wozniacki of Denmark, No. 3 Sloane Stephens of the United States and No. 4 Angelique Kerber of Germany, received first-round byes.

American Venus Williams, who was seeded 16th, withdrew on Saturday due to a right knee injury.